Chinese researchers said Wednesday they have developed a cheap but accurate and easy-to-use paper test that can determine a patient's blood type in as fast as 30 seconds.
In a study published in the U.S. journal Science Translational Medicine, Hong Zhang and his colleagues from China's Third Military Medical University said there is a need to develop "a simple and economical strategy" for fast blood grouping.
That's because conventional approaches, dominated by microplate or gel-column tests, are "encumbered by long turnaround times, labor-intensive operation, and technical training requirements."
Unlike conventional methods, the new paper-based test, however, classified samples into the common ABO and Rh blood groups in less than 30 seconds, Zhang said.
To create the test, the researchers took advantage of chemical reactions between blood serum proteins and a widely-available dye called bromocreosol green.
Each test paper strip was also equipped with antibodies that recognized different blood type markers, such as A or B antigens, which can be found on the surface of red blood cells.
When a drop of blood was applied, the results appeared as visual color changes in the observation window of the paper strip: teal if a blood group antigen was present in a sample and brown if not.
The presence of A or B antigens or both indicates a patient's blood type is A, or B, or AB, while the absence of both A and B antigens indicates blood type O, Zhang said.
The paper-based test was also able to detect antibodies in blood plasma, which can help determine a patient's blood type in full details and only took about two minutes to complete.
After analyzing 3,550 clinical blood samples, the test demonstrated more than a 99.9 percent accuracy rate, and the only inconsistencies occurred in trials with highly uncommon blood types.
"This assay not only provides a new strategy for blood grouping but can also be used in time- and resource-limited situations, such as war zones, in remote areas, and during emergencies," said the study,
"Characterized by an intensified and streamlined workflow capability, the proposed blood-grouping assay may be further developed into highly compact and fully automatic platforms that are highly efficient and economical, making large-scale manufacturing possible."